An energy-saving hydraulic system includes an exerting hydraulic device, a buffering receptacle arranged at one side of the exerting hydraulic device, an impetus hydraulic device connecting to the exerting hydraulic device, and a recovering hydraulic device. The exerting hydraulic device has a loading receptacle selectively disposed at a first high position and a first low position. The impetus hydraulic device has a transferring receptacle selectively disposed at a second high position, a recovering position, and a second low position. The second low position is lower than the buffering receptacle. The recovering hydraulic device connects the exerting hydraulic device and the impetus hydraulic device, and includes a sustaining portion. When the impetus hydraulic device is lowering to the second low position, it contacts the sustaining portion of the recovering hydraulic device to push working liquid to flow back the exerting hydraulic device from the recovering hydraulic device.